Author:

Curtis P. Wagner and Anthony R. Sindt, Ohio Department of Natural Resources

 

Title of Presentation:

Spatial and Temporal Variation of Black Bass Population Dynamics in the Upper Ohio
River: Insights from Five Years of Standardized Sampling

 

Abstract:

Black bass, including largemouth bass Micropterus salmoides, spotted bass Micropterus
punctulatus, and smallmouth bass Micropterus dolomieu, are highly pursued sportfish in the
upper Ohio River. Research has suggested that black bass population dynamics are spatially and
temporally variable across Ohio River pools. To effectively manage these fisheries, biologists
need to understand the variation in abundance, reproductive success, growth, and mortality and
ideally the mechanistic drivers affecting this variation. The purpose of this study is to explore
spatial and temporal trends in the population dynamics of black bass in the Ohio River and
identify correlations with abiotic and biotic factors. During September 2005-2009, population
assessments were conducted every year in four upper Ohio River pools and at least twice in six
other pools using shoreline electrofishing. Largemouth bass were more abundant than
smallmouth and spotted bass in the lower six pools, whereas smallmouth bass were more
abundant than largemouth bass and spotted bass in the upper three pools. Spotted bass were
ubiquitous across pools but catches were generally low. Growth rates were high and did not
exhibit spatial or temporal trends. Reproductive success, indexed by age-0 catch-per-effort, was
highly variable across pools and years. The physical, hydrological, chemical, and biological
characteristics of the Ohio River change substantially over time and across the 724-km reach in
which this study was conducted. Identifying abiotic and biotic factors that correspond to spatial
and temporal variation in black bass population characteristics will help inform the management
of these species in the Ohio River.